A Question of Autumn

Why do leaves change colour in the autumn? It’s a simple question with a simple answer, you might say – they start to die. But there is a bit more to it than that, if you’re interested in the science, and how it can produce some of nature’s most picturesque scenery.

Every autumn the leaves from deciduous trees change colour before falling to the ground. This is due to the fact the leaves contain many chemical pigments, the most important being chlorophyll. Chlorophyll makes leaves green and helps in the process of photosynthesis, which attracts sunlight to the tree, helping them grow. Leaves also contain the chemical carotene, which has a yellow colouring. Carotene lives in the leaves all year, but is masked by the green of the chlorophyll.

The process of leaves turning from green to yellow, red or brown, is dependent on the climate. When autumn approaches and the warmer temperatures of summer begin to dip, the chlorophyll within the leaves begins to break down. Other pigments that live beneath the chlorophyll, such as the carotene, come forward.

Chlorophyll is dependent on water as well as sunshine. As the climate cools and the tree draws colder water up through its roots, the tree prepares for winter. It does this by growing a thin layer of cells over the water tubes in its leaves, closing them up in preparation. Without a regular supply of water, the green chlorophyll starts to disappear and the other colours in the leaf, such as the yellow carotene, can be seen. In some trees, when the leaf cells build, the water blocking wall which seals the tubes in the leaf’s stem traps sugar inside the leaf. This turns the sap and therefore the leaf red, or even purple.

The final part of the process before a leaf falls is when the water within the tree dries up completely. This dehydration kills any remaining green chlorophyll, as well as the yellow and red pigments. Consequently, the leaves turn brown and start to die, becoming dry and crunchy before they fall from the tree.

All in all, it’s quite a complicated and intricate process that provides us with this often beautiful time of year. When it isn’t raining at least!

Today marks the birthday of a man who History has shown to be one of the great pioneers of modern medicine, whose work led to the advent of vaccination. Bearing in mind how much we rely on these to protect us against numerous conditions and diseases now, it is one worth remembering.

Born in Berkeley, Gloucestershire on 17 May 1749, Edward Jenner was the son of the local vicar. He was only 14 years old when he became an apprentice to a surgeon, and began training to be a doctor. Working in the countryside, Jenner noticed that, despite the rife nature of the smallpox disease across England, the milkmaids never suffered from it. They didn’t even show signs of the scarring that commonly affected smallpox sufferers. He did know, however, that the milkmaids often suffered from the far less serious condition of cowpox. Jenner therefore began to work on the theory that perhaps milkmaids did catch the smallpox disease, but had somehow become immune to it.

Taking his thought processes further, Jenner speculated that if you had the relatively harmless cowpox, then perhaps you wouldn’t get the far more lethal disease of smallpox at all. Wanting to prove his theory, in 1796 Jenner carried out his now famous experiment, which involved using a needle to insert pus from Sarah Neales, a milkmaid with cowpox, into the arm of an eight-year-old, James Phipps. A few days later, Jenner then exposed James to the smallpox. The boy failed to contract the disease, and Jenner concluded he was now immune to it. Calling this new method vaccination (after the Latin word vacca, meaning cow), Jenner submitted a paper to the Royal Society the following year about his discovery. It was met with some interest, but further proof was requested. Jenner proceeded to vaccinate and monitor several more children, including his own son.

Although the results of Jenner’s study were published in 1798, his work met with opposition, and even ridicule. It wasn’t until 1853, 30 years after Edward Jenner had died, that his smallpox vaccination was to be made a compulsory injection across both England and Wales. However, Jenner’s work would ultimately lead to a wave of medical innovation, and further, to the large number of life saving vaccinations available today. For this, he is surely worthy of remembrance.

Almost every health scare these days seems to concern viruses. From bird flu and Ebola and now to Zika, these pathogens appear to have medicine on the hop. But what exactly is a virus, and why are viruses such a problem?

A typical virus is a remarkably simple machine. It is just a short stretch of nucleic acid (DNA or RNA) surrounded by a protein coat. The nucleic acid contains coded information for making new virus particles, while the protein coat may help the virus gain access to its host. And that is that. Viruses have no membranes, no complicated machinery for carrying out reactions, and no metabolism like one of your own cells. Viruses do not feed, move, or respond to their surroundings like proper organisms. And they are so small that they were not even visible until 1939, following the development of the electron microscope.

However, introduce a virus into a host cell and the results are dramatic. It hijacks the cell’s processes and redirects them exclusively to the manufacture of more of itself. New virus particles are then budded-off from the surface, each surrounded by a piece of host cell membrane. Or, the cell splits open, releasing hundreds of new particles to infect other cells. Either way, viruses damage and kill our cells, which is what makes us ill when we have a viral infection.

Another trick of viruses provides a hint as to their origins. The genes in our own cells are remarkably like virus particles, also consisting of nucleic acid (DNA in this case) surrounded by protein. Sometimes a virus splices itself into this host DNA like an extra gene. The virus then lies low, being copied with the rest of the DNA when the cell divides, and passing to each of the daughter cells produced. Later, it may emerge without warning to form more viruses in the normal way, causing illness years after it first invaded. This is what happens when the chicken pox virus causes shingles in later life, or when people recovered from Ebola relapse, as recently happened to the Scottish nurse Pauline Cafferkey.

So, if viruses are constructed and can behave just like normal genes, perhaps that’s what they really are? Perhaps they are “escapee genes” that left their cells long ago to take up an independent existence? That would explain why they find it so easy to invade and take over our cells, and why we find it so difficult to defend against them.

Whatever the truth of their ancient origin, viruses present modern medicine with a formidable challenge. Antibiotics do not work against them, and the particles mutate rapidly to keep ahead of vaccines prepared to defeat them. One thing is certain: Ebola and Zika are not the last health scares that they will bring us.

Viruses and the diseases that they cause, including ‘flu and Ebola, are covered in depth by the new A Level Biology course recently launched by Oxford Open Learning. You can find out more about the course here: http://www.ool.co.uk/subject/a-level-biology/

 

By far the biggest killers in today’s Britain are cancer and circulatory disease. Of the 501, 424 people who died in 2014, 29% died of cancer and 27% from heart attacks plus strokes. There is no doubt as to why charities seeking a cure for these scourges attract so much public support.

By contrast, leaving aside ‘flu and pneumonia, which mainly kill the already weakened elderly and infirm, infectious diseases account for a mere 0.6% of deaths. Your chances of being cut down by one of these in your prime of life is comparable with that of the threat from road traffic accidents or suicide. The reason we are dieing largely from heart disease and cancer is not because they are becoming more virulent, then. It is simply because we are living longer. Whereas in 1900 the average life expectancy in this country was just 48, now it is 81.

Antibiotics, the drugs used to treat bacterial infections, are a recent invention. Alexander Fleming stumbled upon them by accident in a London laboratory in 1928, though the first, penicillin, only went into mass-production in 1944. When it did so, it reduced at a stroke the number of deaths from infections, making hospital operations safe, battlefield wounds less fatal, and many serious diseases treatable.

Bacterial resistance to antibiotics emerged as a problem in the 1950s, but it has now become critical. Resistant bacteria have the ability to transfer their resistance to other species as well as passing it on to their offspring. So, once established, resistance to a particular antibiotic spreads rapidly, and bacteria with multiple resistances emerge. By 2004, bacteria resistant to almost all known antibiotics had appeared, while in 2015, bacteria resistant even to the”antibiotic of last resort” appeared in southern China. It is expected to spread to the west shortly.

In April 2014, the World Health Organization (WHO) sounded the alarm on this topic in no uncertain fashion. It spoke of a “major global threat” from such antibiotic-resistant bacteria, and an imminent return to a pre-antibiotic era, where people regularly die from the simplest of infections. If and when this happens, you would be far more likely to die from sepsis following a cut, or from airborne or waterborne bacterium, and less likely to live to an age when cancer and heart disease are a concern.

There is, though, a glimmer of light on this dark horizon. Traditional antibiotics are developed from defensive chemicals produced by fungi and bacteria. However, our own cells also produce chemicals that attack bacteria. They are short proteins (peptides) produced on our own cellular protein-assembly machines, called ribosomes. From this comes their acronym, RAMP antimicrobials (ribosomally synthesized antimicrobial peptides). These antimicrobials carry a positive electrical charge on their molecules and are attracted to the negatively charged outsides of bacterial cells. Once attached to the bacteria, they punch holes in the bacterial wall or membrane, killing the cell.

These natural defence molecules have been around for millions of years, during which time bacteria have failed to develop effective resistance to them. So, if this is the case, and if effective artificial mimics of natural RAMPs can be made, we may yet avoid a potential return to the dark ages of pre-antibiotics.

Bacteria, the discovery and action of antibiotics, and the emergence and spread of resistance, are all covered in depth in the new A level Biology course recently launched by Oxford Open Learning. You can find out more about the course here: http://www.oxfordhomeschooling.co.uk/subject/biology-a-level/

 

HMSBeagle

HMS Beagle moored off the coast of Australia

Charles Darwin was born on February 12th, 1809, in Shrewsbury, Shropshire, England. Although he had no formal education as a botanist or naturalist, Darwin was fascinated by natural history, and dedicated his life to its study.

In July 1838, Charles Darwin presented his paper on his theory of evolution to the respected Linnean Society in London for the very first time.

Having worked on his theory for over twenty years, Darwin’s thoughts on how animals and mankind evolved through a process of natural selection had a major impact on the scientific world and the church. Until Darwin began to share his ideas, ideas about natural history had been dominated by the Church of England, who saw the origins of all living things as working to God’s plan.

Darwin’s theory stated that within a species, individual animals show a wide range of variation. These individual animals with characteristics most suited to their environment are more likely to survive and produce offspring. He also said that the offspring of stronger parents would be more likely to survive than others, as would their own children. By contract, those creatures that are poorly adapted to their environment are less likely to survive, and therefore less likely to successfully reproduce.
Darwin conclude that over a long enough period of history therefore, a species would gradually adapt to best suit its environment, and would evolve into a stronger group. Those species that were weak would die out. This theory became known as ‘Natural Selection’ and coined the phrase ‘The Survival of the Fittest.’

Darwin began writing down his ideas on evolution in 1836, after the end of his five year voyage of discovery on the HMS Beagle. By December 1838 he had developed the main principles of his theory. Over the next few years he went on to refine his ideas with the help of three close supporters, geologist Charles Lyell, botanist Joseph Dalton Hooker and naturalist Thomas Huxley.

The help of Huxley, Lyell, Hooker and others was essential, as Darwin was widely criticized, especially by the church, for his ideas. Ideas, of course, which science has since proved to be correct.

BrainstormingBrainstorming, a method of a group sharing their ideas for a forthcoming project, essay or assignment, was developed in 1953 by Alex Osborn.  This technique is an excellent way of recording existing ideas, and stimulating new ones.

Osborn had four basic rules when brainstorming-:

1. No criticism of other people’s ideas
2. The wilder the idea, the better
3. Aim for quantity of ideas, and quality will follow
4. Try combining ideas to develop new ones

When brainstorming, give yourself a time limit of ten to twenty minutes. Write the subject you are planning to discuss in the centre of a large piece of paper and each time an idea is spoken, draw a line away from the subject and write it down.
As each new idea is developed and written down, your brainstorming mind-map will begin to grow across the page like a spider’s web of potential story, essay, or project ideas.

It is still possible to use this brainstorming technique to create new ideas for your work when you are working on your own. It is an excellent way to make sure you have a note of all the elements you want to include in your next piece of work.
Solo brainstorming is known as clustering.

Once you have written your subject, story character name or project title down in the middle of a sheet of paper, give yourself two minutes to write down all your immediate thoughts. When you’ve done that, look at each of your notes in turn and ask yourself, ‘Why do I think I wrote that?’ Spend two minutes considering each note and add new ones until you have formed a new ‘cluster’ of ideas for each point and have enough information and theories to be able to complete your assignment to the best of your ability.

By creating so many ideas in this way, whether alone or in a group, you can form a far wider breadth of work than you would have done if you’d written a list; and because everyone’s brain has its own memories and experiences, every brainstorming or clustering experience will be unique. Therefore, so will your work. It is this unique quality which makes the brainstorm such a valuable and enduring method.

BronxScienceProgrammingClassroom1960Studying and getting an education is usually associated with passing exams, going to university or making your first foray into a career. However, there are other significant advantages when it comes to making your education a priority.

The development of your cognitive abilities, or thinking skills, and the study of a range of subjects, can be used as a tool for personal fulfilment and true satisfaction with the way you live your life. These advantages are often underestimated or completely unacknowledged by students, yet they represent your opportunity to shape your future.

Cognition is all about how you think, and studying for exams, whether they be A Levels, GCSEs or entry level access courses, develops cognitive abilities. Learning new skills and absorbing previously unfamiliar information allows you to upgrade and update how you make decisions and solve problems, so a good education will help you develop a more analytical, objective approach to making decisions, in the classroom, the office and in general life.

An education is so valuable. As mentioned, it can be instrumental in making major life decisions. Rather than simply dropping you onto a life path that is preset by family, class or where you live, an education encourages you to think about what you want from life, to set goals and aspirations, and to be an active participant in your destiny rather than a passive recipient of circumstance.

If you have developed your cognitive abilities as the result of studying for exams like GCSEs and A Levels, you’re also more likely to make conscious, positive decisions about your physical and mental health. Studying teaches you to question your habits and routines. For example, if you have put on some weight, a good education can enable you to work out the cause and provide the knowledge you need to lose it. If you have been taught to think, you’re more likely to take a considered, measured approach to any problem solving – a skill that can come in useful in many aspects of everyday life.

Getting a great education can also be an excellent means of discovering your talents. Studying as wide a range of subjects as possible will be a great asset in terms of finding out what you’re really passionate about and where your true skills and gifts lie. People often think that a good education is just about passing exams, but the study of a range of subjects at access, GCSE and A Level provides so much more than important pieces of paper. Learning gives you the means to further your personal development. Choose education and you’re in charge of your own destiny!

Lights_out,_sort_of_(2384136179)At 20:30 this coming Saturday night (29th March), people all over the world will participate in Earth Hour by turning off all unnecessary electrical equipment in their homes and businesses. More strikingly, all unnecessary lights will also be switched off, including those of some of the most famous landmarks across the world.

Earth Hour, organised by the WWF (World Wide Fund for Nature), has become increasingly popular since it was first done in 2007.  Back then, it took place in just one city – Sydney, Australia. In 2009, this had increased to 96 participating countries, and, by 2012, participating countries came from each of the seven continents of the world.  Technology giants have also participated in Earth Hour’s history by setting the background of their logos and videos to black, thereby symbolising the lights being turned off. clearly, Earth Hour really is now a worldwide event.

The WWF stresses that Earth Hour is not designed to significantly reduce carbon emissions itself (although many participating cities and countries publish impressive data regarding their decreased electricity consumption during Earth Hour), but instead is intended to raise awareness of environmental issues across the world. In 2012, Earth Hour was extended to include a campaign called I Will If You Will. The idea of IWIYW is that individuals inspire each other by sharing energy saving challenges. Again, technology has played a huge part in promoting the campaign, with IWIYW challenges being posted on YouTube, for example. This extension of the Earth Hour campaign shows that the original goal of the project – that of increasing awareness of and engagement with environmental issues – has been successful.

Obviously, the sheer number of people who participate in Earth Hour across the world (over 1.8 billion in 2011) is inspirational in itself. For this author, though, the images of the famous landmarks without their lights on are the most striking. In previous years, this list of landmarks has included Buckingham Palace, the Eiffel Tower and the Sydney Opera House. There’s something about the symbolism of seeing landmarks so permanent a part of the world’s landscape in such a different way, which makes quite an impact, and really highlights the importance of the environmental issues being discussed.

So, will you be participating in Earth Hour this weekend? If nothing else, try and find some photos of the cities and countries that will be taking part this year. You might want to find out which celebrities are endorsing the campaign and why they’ve chosen to do so  (Last year the UK’s ambassadors were McFly!).  It would be be interesting to hear what you think of the whole thing; is switching the lights off for an hour a meaningful way to engage people in such important issues, or just a bit of a gimmick? Will you one of the millions of people across the globe turning off your lights this Saturday night?

What initial conclusions about the future of GCSE exams can we draw from the mountain of documents which Michael Gove and the Department for Education released last week? And who will the winners and losers be if these proposals come to pass in their current form?

There is no doubt that the new exams will be harder and more “academic”. If not a return to the degree of difficulty posed by the old O-level exams, these new outline specifications match the difficulty and depth of the current IGCSE (International GCSE) specifications set by Edexcel and the Cambridge board. The message seems to have been: take the best of the current IGCSE specs and call it a GCSE instead.

The subject advisers seem to have taken this brief quite literally in most of the core subjects. It is perhaps most clearly seen in Mathematics, a subject in which the IGCSE specifications already require a number of skills that have been beyond the scope of the GCSE Maths syllabuses for 25 years but which are fundamental to AS level Maths. These include function notation, kinematic problems, set notation, rates of change and Venn diagrams, to name but a small sample of topics. There they are in the new drafts in bold print. This is IGCSE Maths by another name.

Most topics are not in bold print, implying that the boundary between what is now the GCSE Foundation and the current GCSE Higher levels is set to shift. Vectors, formerly to be found in the GCSE Higher level requirements, appear in plain text here, including the multiplication of vectors by a scalar. Some maths teachers may need to go on a refresher course to master the required skills!

Similar principles underlie the Science draft. Not only will the individual specifications require considerably more depth of study, as they do in today’s IGCSEs, but the Combined Science qualification will be the equivalent of two GCSEs, not one, just as it is today with IGCSE Science but not GCSE Science. The simple principle behind GCSE Science is to take one-third of the Biology specification, one-third of the Chemistry and one-third of the Physics, while IGCSE takes two-thirds of each of the respective individual subject specifications. The new proposals unashamedly mimic the IGCSE formula.

If this means that all candidates will now face a choice between tackling the new Double Science GCSE or leaving school without any formal recognition of their achievements in the sciences, there will be huge numbers of schoolchildren who fall in the latter category. While the old “everybody passes” philosophy of GCSE had its disadvantages, do we really want to stigmatise a whole generation as incapable of taking and passing the “simplest” of the new science specifications?

 

Oxford Home Schooling is pleased to announce that we now have an exciting new course for IGCSE Human Biology. This follows the recent release of our new course for IGCSE English Literature.

The new course is designed to match the Edexcel 4HB0 specification for examinations in June 2011, June 2012, or later years.

Candidates are required to sit two written examinations. There is no coursework although some familiarity with experimental procedure is required. The specification is designed as ideal preparation for A-level Biology or Human Biology study.

The OOL course is divided into five modules that follow the structure of the Edexcel specification:

Module 1: Cell Processes

Module 2: Human Physiology A

Module 3: Human Physiology B

Module 4: Reproduction and Heredity

Module 5: Microorganisms, Disease and Environment

The Edexcel requirements are a little more “academic” than the equivalent GCSE but our course aims to make the study of Human Biology engaging and practical for students of all abilities.

Human Biology IGCSE may be studied on its own, alongside other Science IGCSEs or as part of a full range of IGCSE studies.

GCSE or IGCSE?

For the home-educated and distance learners in general, 2010 was the last year in which it was possible to stake a “standard” GCSE in Human Biology or Human Physiology and Health. From 2011, GCSE students are required to undertake a controlled assessment which is not practicable unless you are in a supervised classroom. So IGCSE is the only viable choice in this and and a number of other subjects. But there are plenty of IGCSE exam centres up and down the country so it is relatively straightforward to enter the exams, especially with no coursework involved.

IGCSE qualifications are accepted as at least the equivalent of GCSEs in all sixth form colleges, FE colleges, universities and other HE institutions.

IGCSE test centres world-wide

If you are looking to study for IGCSE exams outside the UK, you do not need to visit the UK to sit your exams.  You can find your nearest international exam centre by visiting Edexcel International.

If you are interested in studying this or other IGCSE programmes with Oxford Home Schooling, please contact one of our Student Advisers today.

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